Canon Dr Stephen Palmer had promised to help the 17-year-old with her religious education exams.
But instead he assaulted the girl six times after enticing her to his home while his wife was taking their two young children to school.
Palmer, now 68, touched the teenager intimately as she sat in his study.
On the final occasion, the girl feared she would be raped, Portsmouth crown court heard.
His victim, now 57, said in a statement: “I couldn’t cope with what had happened.